The field of invention is wireless data communications, and in particular transmitting data over a selected bearer service.
The demand for data services that can be accessed via wireless communications devices (i.e., wireless devices) has increased dramatically in recent years. These services place additional demands on the already limited amount of bandwidth that is available over a wireless network.
The increased demand for data services has been addressed by transmitting data on bearer services that carry voice and call control communications, and by deploying additional bearer services directed to data communications. For example, a first-generation cellular system, the Advanced Mobile Phone System (AMPS), included control channels (e.g., reverse control channel, forward control channel) that were used to perform call control (e.g., establish calls). Current North American Time Division Multiple Access (NA-TDMA) systems, also referred to as Interim Standard 136 (IS-136) systems, include a digital control channel (DCCH) that is used to perform both call control and data communications. Data communications carried by the DCCH include short message service (SMS) messages transmitted between a wireless device (e.g., a wireless terminal, a cellular telephone, a computing device coupled to a cellular modem, etc.) and base stations. The DCCH is an example of a broadcast-oriented bearer service for data transmission.
Additional bearer services directed to data communications include: the IS-135 Asynchronous Circuit Switched Data bearer service; the Cellular Digital Packet Data (CDPD) bearer service; and the IS-136 High Speed Packet Data (HSPD) bearer service. The IS-135 bearer service is an example of a connection-oriented bearer service for data transmission. CDPD and HSPD are packet data bearer services that are not connection-oriented bearer services, but rather broadcast-oriented bearer services.
The ability of a DCCH bearer service to transmit data communications is restricted. Use of the DCCH is prioritized to handle call control (e.g., voice call paging traffic) and at the same time allow for limited data transmissions. Increasing the amount of data transmitted over the DCCH can disadvantageously affect the call control operations performed over the DCCH. Data transmissions over the DCCH typically have a high latency. The request/response completion time over the DCCH can have an average range of eighteen to twenty seconds, which corresponds to a simulated average bit rate of 144 to 160 bits per second (bps). Accordingly, the DCCH is an appropriate bearer service for lower-bandwidth, higher-latency data transmissions. Other bearer services, such as the IS-135, CDPD, and HSPD bearer services, are more appropriate bearer services for higher-bandwidth, lower-latency data transmissions. For example, an IS-135 bearer service can provide a bit rate of 9600 bps, a CDPD bearer service can support the transmission of packet data at bit rates of up to 19.2 Kbps, and proposed HSPD bearer services can provide bit rates of up to 300 Kbps. For purposes of this invention, a high bandwidth bearer service can deliver approximately ten or more times the bandwidth of a low bandwidth bearer service.
Known methods of transmitting data over wireless communications networks do not direct certain data services to selected bearer services. FIG. 1 shows a known system for providing data services over a wireless network, which system is taught by U.S. Pat. No. 5,673,322 to Pepe et al., issued Sep. 30, 1997. Wireless device 10 can be coupled to base station 20 via wireless connection 21, and base station 20 is coupled to server 30 by a wired connection. The term xe2x80x9ccoupledxe2x80x9d means connected directly or indirectly. Thus, A is xe2x80x9ccoupledxe2x80x9d to C if A is directly connected to C, and A is xe2x80x9ccoupledxe2x80x9d to C if A is connected directly to B, and B is directly connected to C. Wireless communications device 10 includes a local data compression/decompression proxy 15 to compress data transmissions to server 30 and decompress data transmissions from server 30. Likewise, server 30 includes a remote data compression/decompression proxy 25 to decompress data transmissions from wireless device 10 and compress data transmissions to wireless device 10. Data transmissions between wireless device 10 and server 30 utilize less bandwidth of wireless connection 21 when they are compressed and decompressed by local data compression/decompression proxy 15 and remote data compression/decompression proxy 25.
Data compression/decompression techniques can enable greater amounts of data to be transmitted over the DCCH and other bearer services, but the transmission of too much compressed data over the DCCH can disadvantageously affect the ability of carriers to provide call control for voice services.
In view of the foregoing, a substantial need exists for directing certain data transmissions to selected bearer services.
The present invention provides a method and apparatus for transmitting data to a wireless communications device over a selected bearer service. In one embodiment of the present invention, a service message, including a device application identifier and a bearer service indicator, is generated and sent to a wireless communications device.